Electric battery



Original Filed Sept. 29, 1932 H 1 Pari L fer/Paz wf f f l l l l sra/vanua 12,/1

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@zy-.MMM wg Patented' Apr. 21, 1936 lPfrxazN'r OFFICE' ELECTRIC BATTERY Artur Rudolf, Berlin,. Germany,

assigner to The Rulag Battery Company Limited, London, England Original application September 29, 1932, Serial No. 635,339. Divided and this application August 8, 1933, October 5, 1931 Serial No. 684,243. In Germany s claims. (o1. 13s-135) The present invention is Jfor improvements in or relating to electric batteries, and constitutes a division of my application Serial Number 635,339, filed September 29, 1932.

nIn connection with electric batteries and more especially lead cells, the difilculty has been experienced hitherto of leading the conductors lwhich connect the electrodes to the external terminals of the battery, through a. wall or lid of the cell in such a manner as to form a joint impervious to electrolyte. The "creep of electrolyte occurs chiefly along the conductors of the positive electrodes and is probably due to the oxidation of the conductor by electro-chemical action, the oxide layer providing a path for the electrolyte.

One method frequently employed hitherto for sealing a. conductor into the lid of a cell consists in pouring over the lid and around the terminals thereon, a substance which subsequently hardens. This method can only be employed, however, if the lid consists of rigid material to which the substance adheres firmly. Moreover, the conductor must be thoroughly dried and polished prior to adding the said substance which must be of considerable thickness, at least where it surrounds the conductor.

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Such a method cannot be conveniently em ployed in the case of small lead cells, for example, for pocket lamps, where it is absolutely essential to preventA escape of acid and where the dimensions of the cell must be kept as small as possible.

It is an object of the present invention to provide an acid-proof joint between the wall of a 35 cell and the conductor which connects an electrode to an. external terminal. According to the present invention there is provided a lead cell comprising a casing arranged to hold an electrolyte, an electrode arranged with- 40 in the casing, a terminal arranged externally of the casing, and an electrical conductor arranged to connect the electrode to the external terminal characterized by the provision of means for preventing access of electrolyte to the conductor over 45 the whole or a part of that portion of the conductor which extends from the surface of the With this arrangement chemical action can' proceed only on those portions of the conductor, which are located inside thecell and are not covelectrolyte to the external terminal. Preferably ered by the protecting envelope. Since a portion of the conductor must be soldered or otherwise secured to the electrode, it will be inconvenient to cover the conductor over'its entire length, but the length of covered conductor can be so chosen without considerable increase in space, that it is practically impossible for chemical action to proceed under the protective covering a sufcient distance to reach the terminal.

A convenient length of the conductor may be obtained by providing a helix thereof between the point where it enters the cell and the electrode, the helical portion being covered withthe pro-4 tecting envelope in accordance with the invention. Other methods of ensuring that the chemical action does not proceed as far as the external electrode will be hereinafter described.

When applying the protecting cover to the conductor it is essential that the protecting cover `which consists of acid-proof material, should adhere closely to the conductor. The latter must therefore be as clean and polished as possible. There are a number of acid-proof materials which may be employed for'forming the protective covering. The most?` convenient material is celluloid which is preferably applied to the conductor in the form of a thin seamless lm of celluloid varnish. Any other suitable material, such as artificial resin and the like, may be employed instead of celluloid and may be applied either by spraying or by pressing a thin lm of the material on to the conductor.

It is,l in many cases, diillcult to apply to the conducting tags of the plate a protecting cover which adheres perfectly thereto. In such cases, it is proposed in accordance with 'a further feature of the invention to make the conductor from the electrode to the external terminal of the cell in two or more conducting parts, namely an cuter conductor and an inner-conductor. The outer conductor extends through the cell wall and is connected toan external terminal of the cell, whilst the inner conductor connects the outer conductor to the electrode tag. Both conductors, or at least the outer conductor are provided with-a protecting cover according to the invention. I'he inner conductor may be connected to the electrode tag by soldering. A cnductor comprising two or more conducting' parts,

one or more of which are enveloped wholly or in part in a protecting cover, hasthe advantage damp plates, the protected part of theA conductor,

that, when'the cell is built up from charged acidlength with a covering of celluloid in a liquid tight manner before the container comes into contact with acid.

It is also possible to protect the conductor or one or more parts thereof against the action of the electrolyte by embedding these parts for a sufficient distance in the wall of the container which, thereby acts as a closely fitting protecting cover for the conductor. This method is particularly well suited in cases where the conductor consists of several parts as it is then possible to embed a part of the conductor in the wall of the container at the time of constructing the wall, which may be eifected by casting, pressure or spraying.

Although, as a rule, the positive conductor is more subject to chemical action than the negative, it has nevertheless been proved to be of advantage, to construct the conductors of the negative as well as of the positive plates according to the invention, and they may then be arranged vin the cell in such a manner, that they rest between the plates, and serve as separators therefor.

The invention will be more particularly described with reference to the accompanying drawing, in which:-

Figure 1 is a vertical section on an enlarged scale of a battery for a pocket lamp constructed in accordance with the invention and taken on the line I-I of Figure 2, 1 f

Figures 2 and 3 are end and side elevations respectively of the battery shown in Figure l, a portion ofthe casing being broken away in Figure 3 to illustrate the internal construction of the battery.

Figure 4 is :a side elevation partly in section illustrating a modied form of battery constructed in accordance with this invention in which the conductors are embedded or moulded in the side wall of the casing.

Figure 5 is a sectional view on the line 6 5 of Figure 1, and

Figure 6 is a View similar to Figure 5, illustrating a modified construction in which the conductors extend through a bore or channel blown or otherwise formed in the side wall of the casing.

Referring to the drawing, a battery comprises a four-sided celluloid casing 5 having two end celluloid walls 6 and l which are subsequently secured to the shell by means of an adhesive in such a manner that the casing is rendered gastight.

Prior to securing the end wall 6 in position, there are introduced through two holes therein, two lead conductors 8 and 9 which have been previously coated for the major portion of their III. 'I'he conductors and 9 are of such a length that when introduced into the shell they extend beyond the other end thereof and are at the same time arranged to form a liquid tight joint with the end cover 6. The end cover 6 when placed in position is cemented to the side walls of the casing so'as to form a liquid tight joint therewith.- The cup shaped member formed by the shell 5 and the end cover 6 is thereupon filled with an 4electrolyte II of paste-like consistency and the positive and the negative electrodes I2 and I l which are preferably constructed in accordance with the invention claimed in United States patent application Serial No. 635,339 are introduced into the said cups so that the lugs I4 or I5 thereof extend .from the Open end of the cup in a like-manner .to the conductors l and 9 above referred to. A

second end cover Il formed of a piece of celluthe electrolyte.

. no lead on the surface .loid having a series of holes therein is then threaded over the conductors 8 and 9 and the and I5 and the conductors 8 and 9 are connectedY to one another by means of lead burning, the

lugs I4 being connected to the conductors 9 whilst the lugs I5 of the negative electrode are connected to the conductor 8, the conductors so united are thereupon pressed into the false bottom of the shell which is covered by the end cover 1 which is cementedupon the open end of the casing so as to form the true bottom of the finished shell.

Instead of introducing the lead conductors 8 and 9 through the end cover 6 of the casing, they may, if necessary, be moulded into the side walls of the shell as is shown in Figures 4 and 5, or they may be introduced through holes Il blown in the direction of the length of the wall' of the shell as shown in Figure 6 so as to ensure in both cases that the conductors are protected from the electrolyte for the major portion of their length as they extend from the top" to the bottom of the cell.

Itis well known that when charging lead cells, gases are formed which, in the usual lead-accumulators escape through a hole specially provided therefor inthe wall of the cell. On the other hand, if a cell is not charged it may, in addition to being constructed as described above be made gas-tight and acidtight, so that it is impossible to re-open the cell without destroying the container. The purpose of this is to remove all possibility of the electrolyte escaping. but it has also been demonstrated that the gas-tight closing of the inside of the cell against the atmosphere has a marked influence on the shelf-life of such cells. By this means water is prevented from evaporating from the thickened electrolyte and the oxygen of the air cannot reach Further, it has also been found that, in lead cells such as have been described above which are used only once, it is preferable to use plates.

which are made by compression, for example,

Serial No. 635,339. As cial lead carrier-frame, the capacity of the cell 'in comparison with the weight thereof but it also ensures that there is of the plates and consequently improves the storing properties of the cell.

What I claim and desire to secure by Letters Patent of the United States is:-

1. A lead cell which comprises in combination, a casing arranged to hold an electrolyte, at least one positive and one negative electrode arranged within said casing in spaced relation, and at least one conductor for the positive electrode and at least one corresponding conductor for the negative electrode, .each of said conductors extending internally and externally of the casking to form the respectiveelectrical connections for the positive and conductors each being ing with a protective ing insulating material negative electrodes, said provided within thecascovering of acid resistarranged .to prevent direct contact between. the electrolyte` and said conductors to preclude creeping of the electrolyte to the external portions insulated portionl of at least one of said conductors extending between two adjacent positive the plates through .fissures in of said conductors, the

and negative electrodes from the point of connection to an electrode toward a remote end .thereof to maintain the said electrodes spaced -least one conductor for the positive electrode and at least one corresponding conductor for the negative electrode, each of said conductors extending internally and externally of the casing and being of a length equal at least to the length of one of said electrodes, each of said conductors being connected to that end of the corresponding electrode which is remote from that portion of the casing from which the corresponding conductor extends, said conductors being each provided within the casing with a protecting covering of acid resisting insulating material arranged to prevent direct contact between said conductors and the electrolyte to preclude creeping of the electrolyte to the external portions of the conductors, the insulated portion of at least one of said conductors extending between two adjacent positive and negative electrodes from the point of connection to an electrode toward the opposite end thereof to maintain the said electrodes spaced a distance notless than the thickness of said conductors..

the whole of that portion of any conductor which is protected by said covering of insulating material being immune to ,the action of the electrolyte whereby to act as a separator for the electrodes.

3. A lead cell comprising in combination a casing arranged to hold an electrolyte, at least one positive and at least one negative electrode arranged within the casing in spaced relation, and at least one conductor for the positive electrode and at least one conductor for the negative electrode, said casing including outer cover members at opposite ends thereof and an inner false cover member arranged in spaced relation to one of said outer cover members and` denning therewith a compartment within the casing, each of said conductors including two portions, one portion of each conductor being connected to the vrespective electrodes and lying within said compartment, the other portion of each electrode being connected to said first portion within said compartment and extending therefrom through said inner false cover member, through that portion of the casing occupied by the electrolyte and between two adjacent positive and negative electrodes and thence extending exteriorly of the casing through the outer end cover member remotefrom said compartment, the portions of the conductors passing through the electrolyte being provided with protecting sheaths vof acid resisting insulating material to prevent the electrolyte from creeping to the exterior portions of the conductors and to maintain said electrodes out of contact with each other.

ARTUR. RUDOLF. 

